Raising the Ceiling of Diastereoselectivity in Hydrogen Transfer on Acyclic Radicals

被引：6

作者：

Denissova, Irina ^{[1
]}

Maretti, Luca ^{[4
]}

Wilkes, Brian C. ^{[1
]}

Scaiano, J. C. ^{[4
]}

Guindon, Yvan ^{[2
,3
]}

机构：

[1] Inst Rech Clin Montreal, Montreal, PQ H2W 1R7, Canada

[2] Univ Montreal, Dept Chem, Montreal, PQ H3C 3J7, Canada

[3] McGill Univ, Dept Chem, Montreal, PQ H3A 2K6, Canada

[4] Univ Ottawa, Dept Chem, Ottawa, ON K1N 6N5, Canada

来源：

JOURNAL OF ORGANIC CHEMISTRY | 2009年 / 74卷 / 06期

基金：

加拿大自然科学与工程研究理事会;

关键词：

BETA-ALKOXY ESTERS; RECEPTOR-BOUND CONFORMATION; ENHANCE STEREOSELECTIVITY; N-ACYLOXAZOLIDINONE; LEWIS-ACIDS; ALPHA-HALO; CHELATION; REDUCTION; ALKYL; STEREOCHEMISTRY;

D O I：

10.1021/jo802634w

中图分类号：

O62 [有机化学];

学科分类号：

070303 ; 081704 ;

摘要：

We report here that the monodentate complexation of Me2AlCl to an ester group significantly enhances the selectivity of hydrogen transfer on acyclic radicals flanked by both an ester functionality and a stereogenic center, leading to C-2,C-3-anti products with high diastereoselectivity. In certain cases improved ratios were obtained using bulkier aluminum Lewis acid such as MAD (methylaluminum-di(di-2,6-tertbutyl-4-methylphenoxide). Electron spin resonance studies on these acyclic radicals indicate that Lewis acid complexation leads to conformational changes in the radicals. The stereochemistry of the preferred enolate radicals complexed with Lewis acids and their impact on the acyclic transition states involved are suggested.

引用

页码：2438 / 2446

页数：9

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